Process for the production of gasoline blending components and aromatic hydrocarbons from lower alkanes

ABSTRACT

An integrated process for producing gasoline blending components and aromatic hydrocarbons which comprises: (a) contacting a lower alkane feed with an aromatic hydrocarbon conversion catalyst to produce an aromatic reaction product mixture which is comprised of benzene and/or toluene and/or xylene, C 9  aromatic products, C 10  aromatic products including naphthalene and, optionally, C 11+  aromatic products, (b) separating and recovering the aromatic reaction product mixture, (c) separating and recovering benzene, (d) optionally separating recovering toluene and/or xylene, and (e) separating and recovering the C 9  aromatic products and the C 10  aromatic products which boil at a lower temperature than naphthalene from the naphthalene and the C 10  aromatic reaction products which boil at a higher temperature than naphthalene and any C 11+  aromatic products.

This is a divisional application of U.S. patent application Ser. No.13/082,756, filed Apr. 8, 2011, which claims priority to U.S.Provisional Application No. 61/323,017, filed on Apr. 12, 2010, which isherein incorporated by reference.

FIELD OF THE INVENTION

The present invention relates to a process for producing gasolineblending components and aromatic hydrocarbons from lower alkanes. Theinvention also relates to a novel gasoline blending component.

BACKGROUND OF THE INVENTION

There is a projected global shortage for benzene which is generallyobtained, along with other aromatic hydrocarbons, by separating afeedstock fraction which is rich in aromatic compounds, such asreformate produced through a catalytic reforming process and pyrolysisgasolines produced through a naphtha cracking process, from non-aromatichydrocarbons using a solvent extraction process. To meet this projectedsupply shortage, numerous catalysts and processes for on-purposeproduction of aromatics (including benzene) from alkanes containing sixor less carbon atoms per molecule have been investigated. For example,U.S. Pat. No. 4,350,835 describes a process for convertingethane-containing gaseous feeds to aromatics using a crystalline zeolitecatalyst of the ZSM-5-type family containing a minor amount of Ga. Asanother example, U.S. Pat. No. 7,186,871 describes aromatization ofC₁-C₄ alkanes using a catalyst containing Pt and ZSM-5.

It is well known to add certain blending components to gasolines toimprove the properties thereof such as the RON or the MON. Commonly usedblending components include naphthas (e.g., straight-run gasoline,alkylate, reformate, toluene, xylene), cracked gasoline, pyrolysisgasoline, and paraffinic hydrocarbons.

U.S. Pat. No. 6,353,143 describes fuel compositions which are comprisedof a branched hydrocarbon, such as an isoparaffin, and an aromatichydrocarbon. An example of a suitable aromatic hydrocarbon given isAROMATIC 150 Fluid from Exxon Chemical which typically is composed of anarrow-cut aromatic solvent containing about 23 wt. % tetra-methylbenzenes, about 22 wt. % ethyl dimethyl benzenes, about 15 wt. % mono-,di- and tri-methyl indanes, about 8 wt. % diethyl benzenes, about 8 wt.% naphthalene, about 5 wt. % trimethyl benzenes, about 2 wt. % indane,and about 1 wt. % or less of methyl ethyl benzenes, propyl benzenes,methyl propyl benzenes, butyl benzenes, hexyl benzenes, indene, methylnaphthalenes, and xylenes. Another example of an aromatic hydrocarbongiven is AROMMATIC 100 which typically is composed of a narrow-cutaromatic solvent containing about 40 wt. % trimethyl benzenes, about 35wt. % methyl ethyl benzenes, about 1 wt. % propyl and isopropylbenzenes, about 3 wt. % ethyl dimethyl benzenes, about 2 wt. % methyl(n- and iso-) propyl benzenes, about 2 wt. % diethyl benzenes, less thanabout 1 wt. % each of mono butyl benzenes and tetramethyl benzenes,about 6 wt. % xylenes, and minor amounts of ethyl benzene and C₁₀-C₁₁saturates.

SUMMARY OF THE INVENTION

The present invention provides an integrated process for producinggasoline blending components and aromatic hydrocarbons which comprises:

-   -   (a) contacting a lower alkane feed with an aromatic hydrocarbon        conversion catalyst to produce an aromatic reaction product        mixture which is comprised of benzene and/or toluene and/or        xylene, C₉ aromatic products, C₁₀ aromatic products including        naphthalene and, optionally, C₁₁₊ aromatic products,    -   (b) separating and recovering the aromatic reaction product        mixture,    -   (c) separating and recovering benzene, and    -   (d) separating and recovering toluene and/or xylene and the C₉        aromatic products and the C₁₀ aromatic products which boil at a        lower temperature than naphthalene from the naphthalene and the        C₁₀ aromatic reaction products which boil at a higher        temperature than naphthalene and any C₁₁₊ aromatic products.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow diagram of a two stage aromatization process whereinbenzene, toluene and/or xylene and the C₉₋₁₀ fraction are recoveredseparately.

FIG. 2 is a flow diagram of a two stage aromatization process whereinthe process also comprises hydrodealkylation of the toluene and xyleneto make additional benzene.

FIG. 3 is a flow diagram of the two stage aromatization process whereinthe C₉₋₁₀ fraction is recovered together with the toluene and xylene asa single gasoline blending component.

DETAILED DESCRIPTION OF THE INVENTION

Gasolines typically comprise mixtures of hydrocarbons boiling in therange from 25 to 230 ° C. (EN-ISO 3405), the optimal ranges anddistillation curves typically varying according to climate and season ofthe year. The hydrocarbons in a gasoline may be derived by any meansknown in the art, conveniently the hydrocarbons may be derived in anyknown manner from straight-run gasoline, synthetically-produced aromatichydrocarbon mixtures, thermally or catalytically cracked hydrocarbons,hydro-cracked petroleum fractions, catalytically reformed hydrocarbonsor mixtures of these.

The specific distillation curve, hydrocarbon composition, researchoctane number (RON) and motor octane number (MON) of the gasoline arenot critical. Conveniently, the research octane number (RON) of thegasoline may be at least 80, for instance in the range of from 80 to 110(EN 25164). The motor octane number (MON) of the gasoline mayconveniently be at least 70, for instance in the range of from 70 to 110(EN 25163).

Gasoline is composed of many different hydrocarbons. Typically, gasolinecomprises components selected from one or more of the following groups;saturated hydrocarbons, olefinic hydrocarbons, aromatic hydrocarbons,and oxygenated hydrocarbons. Typically, the aromatic hydrocarbon contentof the gasoline may be in the range of from 0 to 70 percent by volumebased on the gasoline (ASTM D1319).

Crude oil enters a refinery and is processed through various unitsbefore being blended into gasoline. A refinery may have a fluidcatalytic cracker (FCC), an alkylate unit, and a reformer, each of whichproduces gasoline blending components. Alkylate gasoline, for example,is valuable because it has a very high octane, and can be used toproduce high-octane (and higher value) blends. Light straight rungasoline is the least processed stream. It is cheap to produce, but ithas a low octane. The person specifying the gasoline blends has to mixall of the components together to meet the product specifications.

It is well known to add certain blending components to gasoline toimprove the properties thereof such as the RON or the MON. Commonly usedblending components include naphthas (e.g., straight-run gasoline,alkylate, reformate, benzene, toluene, xylene), cracked gasoline,pyrolysis gasoline, and paraffinic hydrocarbons. The present inventionprovides a novel gasoline blending component which comprises from about1 to 10 wt % indane, from about 40 to 60% wt indene, from about 4 to 20wt % C₉ aromatics other than indane or indene, and from about 25 to 35wt % C₁₀ aromatics other than naphthalene.

The process of the present invention comprises bringing into contact ahydrocarbon feedstock containing lower alkanes, and possibly otherhydrocarbons, and a catalyst composition suitable for promoting thereaction of such hydrocarbons to aromatic hydrocarbons, such as benzene,at a temperature from about 400 to about 700° C. and a pressure fromabout 0.01 to about 1.0 Mpa absolute. The gas hourly space velocity(GHSV) per hour may range from about 300 to about 6000. The process maybe carried out in a single stage or in multiple, preferably two, stages.If a two-stage process is used, the conditions in each stage may fall inthe above ranges and may be the same or different.

Suitable feed streams for use herein include alkane streams which maycontain primarily one or more C₂, C₃, and/or C₄ alkanes (referred toherein as “lower alkanes”), for example an ethane/propane/butane-richstream derived from natural gas, refinery or petrochemical streamsincluding waste streams. Examples of potentially suitable feed streamsinclude (but are not limited to) residual ethane and propane fromnatural gas (methane) purification, pure ethane, propane and butanestreams (also known as Natural Gas Liquids) co-produced at a liquefiednatural gas site, C₂-C₅ streams from associated gases co-produced withcrude oil production, unreacted ethane “waste” streams from steamcrackers, and the C₁-C₃ byproduct stream from naphtha reformers. Thelower alkane feed may be deliberately diluted with relatively inertgases such as nitrogen and/or with various light hydrocarbons and/orwith low levels of additives needed to improve catalyst performance.

In one embodiment, the majority of the feedstock is comprised of ethaneand propane. In another embodiment, the feedstock is comprised of mixedC₂-C₄ alkanes. In still another embodiment, the feedstock is comprisedof primarily propane and butane. The feedstock may contain in additionother open chain hydrocarbons containing between 3 and 8 carbon atoms ascoreactants. Specific examples of such additional coreactants arepropylene, isobutane, n-butenes and isobutene. The feed may contain upto about 20 weight percent of C₂-C₄ olefins, preferably no more thanabout 10 weight percent olefins. Too much olefin content may cause anunacceptable amount of coking. The hydrocarbon feedstock preferably maybe comprised of at least about 30 percent by weight of C₂₋₄hydrocarbons, preferably at least about 50 percent by weight.

In one embodiment, the lower alkane feed is comprised of at leastpropane and ethane and the process is carried out in two stages asdescribed in copending, commonly assigned provisional U.S. PatentApplication No. 61/257,085, entitled Process for the Conversion MixedLower Alkanes to Aromatic Hydrocarbons, filed Nov. 2, 2009, which isherein incorporated by reference in its entirety. In the first stage,the reaction conditions may be optimized for the conversion of propaneto benzene. In the second stage, reaction conditions may be optimizedfor the conversion of ethane to benzene. Optionally, the second stagereaction conditions may also be optimized for the conversion to BTX ofany other non-aromatic hydrocarbons which may be produced in the firststage.

In another embodiment, as described in copending, commonly assignedprovisional U.S. Patent Application No. 61/257,149, entitled Process forthe Conversion Lower Alkanes to Aromatic Hydrocarbons, filed Nov. 2,2009, which is herein incorporated by reference in its entirety, theprocess (a) comprises alternately contacting the lower alkane feed withan aromatization catalyst in a reactor for a short period of time,preferably 10 minutes or less, and then contacting the aromatizationcatalyst with hydrogen at elevated temperature for a short period oftime, preferably 20 minutes or less, (b) repeating the cycle of step (a)at least one time, (c) regenerating the aromatization catalyst bycontacting it with an oxygen-containing gas at elevated temperature, and(d) repeating steps (a) through (c) at least one time.

One important advantage of the aromatization process used herein is thatlittle or no C₅₊ non-aromatic hydrocarbons are produced. The C₁₋₄non-aromatic hydrocarbons which are produced may be recycled or used forfuel, etc. The major products produced are aromatic. Benzene, andgenerally toluene and xylene, are recovered, leaving a substantialamount of C₉₊ aromatic hydrocarbons. We have discovered that asignificant portion of the C₉₊ fraction produced from lower alkanes inthis aromatization process may be used as a gasoline-blending componentwith attractive properties. Accordingly, a product separation scheme isincorporated in the aromatization process to efficiently separate andrecover the desirable portion of the C₉₊ mixture so that a maximumamount of desirable gasoline blending component is obtained. The C₉₊fraction includes naphthalene and higher boiling C₁₀₊ aromatichydrocarbons which are not useful for gasoline blending componentsbecause its boiling range is higher than specified/typical gasolinerange.

In the present invention, the C₉ aromatic hydrocarbons and the C₁₀aromatic hydrocarbons which boil at lower temperatures than naphthaleneare recovered separately. The C₉ aromatic hydrocarbons include indane,indene, durene, propylbenzene, etc. and the lower boiling C₁₀ aromatichydrocarbons include methylindane, methylindene, methylpropylbenzene,butylbenzene, diethylbenzene, etc. The combined C₉ aromatic hydrocarbonsand C₁₀ aromatic hydrocarbons which boil at lower temperatures thannaphthalene comprise the gasoline blending component of the presentinvention. It may comprise from about 1 to 10 wt % indane, from about 40to 60 wt % indene, from about 4 to 20 wt % C₉ aromatics other thanindane or indene, and from about 25 to 35 wt % C₁₀ aromatics other thannaphthalene.

Indane is a hydrocarbon petrochemical compound with chemical formulaC₉H₁₀. Derivatives include compounds such as 1-methyl-indane and2-methyl-indane (where one methyl group is attached to the five carbonring), 4-methyl-indane and 5-methyl-indane (where one methyl group isattached to the benzene ring), various dimethyl-indanes, and variouspharmaceutical derivatives. Indene is an unsaturated polycyclichydrocarbon with chemical formula C₉H₈. It is composed of a benzene ringfused with a cyclopentene ring.

Multiple chemical analyses of the C₉₊ fraction obtained experimentallyshow that indane and indene form the majority of the C₉ molecules whilemethyl substituted indane and indene and naphthalene form the majorityof the C₁₀ molecules. Indane and indene

are similar in structure to benzene, ethyl benzene and propyl benzenewhich are known to have high octane and high flame speed boostingproperties as shown in Table 1.

TABLE 1 Flame Speed Compound RON MON cm/sec b.p. ° C. Benzene 105 99 8480.1 Toluene 120 109 67.9 110.6 Isooctane 100 100 67 98.5 Ethylbenzene111.2 97.9 76.9 136.2 1,2,4 Trimethylbenzene 110.5 105.8 58.3 169.4(Pseudocumene) 1,3,5 Trimethylbenzene (Mesitylene) 120.3 120.3 56 164.7isopropylbenzene 113.1 99.3 76.3 152.4 n-propylbenzene 74.1t-butylbenzene 75.7

FIG. 1 is a flow diagram of a two stage aromatization process wherein aC₉₋₁₀ only fraction is recovered. Lower alkane feed enters stage 1aromatization reactor 2 through line 1. The reaction products arecombined with the reaction products from stage 2 aromatization reactor 3in line 4 which is conveyed to a vapor-liquid separator 5. The liquidbottoms leave the separator 5 in line 6 and are conveyed to thedebenzenizer 7 wherein benzene is separated from the other aromaticproducts and is recovered in line 8. The other aromatic products in thebottom stream 9 are conveyed to the toluene-xylene-C₉₋₁₀ separationstage 10. The toluene and xylene leave separation stage 10 through line11 and are recovered separately as toluene in line 12 and xylene in line13. The C₉₋₁₀ fraction is taken out of separation stage 10 and recoveredin line 14. The remaining C₉₋₁₀₊ aromatics leave stage 10 through line15.

Vapor stream 16 leaves separator 5 and is compressed in compressor 17.Any aromatics carried over to the compressor are conveyed to thedebenzenizer 7 through line 18. The other liquids are conveyed throughline 19 to demethanizer 20 wherein the methane and hydrogen areseparated and recovered as fuel gas in line 21. The bottom stream 22 ofthe demethanizer 20 contains C₂₄ hydrocarbons which are recycled to thesecond stage aromatization reactor 3.

FIG. 2 is a flow diagram of the two stage aromatization process whereinthe process scheme of FIG. 1 includes at the end a hydrodealkylationsection wherein the toluene and xylene are reacted to produce morebenzene. Most of the process description is the same as for FIG. 1.Instead of being separated, the toluene and xylene in line 11 areconveyed to a hydrodealkylation unit 26 which produces additionalbenzene in line 28 and some fuel gas components in line 29. Unreactedtoluene and xylene are recycled to the debenzenizer through line 27. Theoverhead stream 21 from demethanizer 20 is conveyed to separator 23which separates hydrogen from other fuel gas components. The hydrogen isconveyed through line 25 to the hydrodealkylation unit 26. The remainingfuel gas components from separator 23 are combined with line 29 andrecovered as fuel gas through line 24.

FIG. 3 is a flow diagram of a two stage aromatization process whereinthe C₉₋₁₀ fraction is recovered together with the toluene and xylene asa single gasoline blending component. In this embodiment, the toluene,xylene and the C₉₋₁₀ fractions are not recovered separately but arerecovered together as a combined gasoline blending component in line 11.

Any one of a variety of catalysts may be used to promote the reaction ofthe lower alkanes to aromatic hydrocarbons. One such catalyst isdescribed in U.S. Pat. No. 4,899,006 which is herein incorporated byreference in its entirety. The catalyst composition described thereincomprises an aluminosilicate having gallium deposited thereon and/or analuminosilicate in which cations have been exchanged with gallium ions.The molar ratio of silica to alumina is at least 5:1.

Another catalyst which may be used in the process of the presentinvention is described in EP 0 244 162. This catalyst comprises thecatalyst described in the preceding paragraph and a Group VIII metalselected from rhodium and platinum. The aluminosilicates are said topreferably be MFI or MEL type structures and may be ZSM-5, ZSM-8,ZSM-11, ZSM-12 or ZSM-35.

Other catalysts which may be used in the process of the presentinvention are described in U.S. Pat. No. 7,186,871 and U.S. Pat. No.7,186,872, both of which are herein incorporated by reference in theirentirety. The first of these patents describes a platinum containingZSM-5 crystalline zeolite synthesized by preparing the zeolitecontaining the aluminum and silicon in the framework, depositingplatinum on the zeolite and calcining the zeolite. The second patentdescribes such a catalyst which contains gallium in the framework and isessentially aluminum-free.

Additional catalysts which may be used in the process of the presentinvention include those described in U.S. Pat. No. 5,227,557, herebyincorporated by reference in its entirety.

These catalysts contain an MFI zeolite plus at least one noble metalfrom the platinum family and at least one additional metal chosen fromthe group consisting of tin, germanium, lead, and indium.

One preferred catalyst for use in this invention is described in U.S.Patent Application Publication No. 2009/0209795. This publication ishereby incorporated by reference in its entirety. This publicationdescribes a catalyst comprising: (1) 0.005 to 0.1% wt (% by weight)platinum, based on the metal, preferably 0.01 to 0.05% wt, (2) an amountof an attenuating metal selected from the group consisting of tin, lead,and germanium, which is no more than 0.02% wt less than the amount ofplatinum, preferably not more than 0.2% wt of the catalyst, based on themetal; (3) 10 to 99.9% wt of an aluminosilicate, preferably a zeolite,based on the aluminosilicate, preferably 30 to 99.9% wt, preferablyselected from the group consisting of ZSM-5, ZSM-11, ZSM-12, ZSM-23, orZSM-35, preferably converted to the H+ form, preferably having aSiO₂/Al₂O₃ molar ratio of from 20:1 to 80:1, and (4) a binder,preferably selected from silica, alumina and mixtures thereof.

Another preferred catalyst for use in this invention is described in PCTPublication No. WO 2009/105447. This publication is hereby incorporatedby reference in its entirety. The publication describes a catalystcomprising: (1) 0.005 to 0.1% wt (% by weight) platinum, based on themetal, preferably 0.01 to 0.06% wt, most preferably 0.01 to 0.05% wt,(2) an amount of iron which is equal to or greater than the amount ofthe platinum but not more than 0.50% wt of the catalyst, preferably notmore than 0.20% wt of the catalyst, most preferably not more than 0.10%wt of the catalyst, based on the metal; (3) 10 to 99.9% wt of analuminosilicate, preferably a zeolite, based on the aluminosilicate,preferably 30 to 99.9% wt, preferably selected from the group consistingof ZSM-5, ZSM-11, ZSM-12, ZSM-23, or ZSM-35, preferably converted to theH+form, preferably having a SiO₂/Al₂O₃ molar ratio of from 20:1 to 80:1,and (4) a binder, preferably selected from silica, alumina and mixturesthereof.

Another preferred catalyst for use in this invention is described inU.S. Patent Application Publication No. 2009/0209794. This publicationis hereby incorporated by reference in its entirety. This publicationdescribes a catalyst comprising: (1) 0.005 to 0.1 wt % (% by weight)platinum, based on the metal, preferably 0.01 to 0.05% wt, mostpreferably 0.02 to 0.05% wt, (2) an amount of gallium which is equal toor greater than the amount of the platinum, preferably no more than 1 wt%, most preferably no more than 0.5 wt %, based on the metal; (3) 10 to99.9 wt % of an aluminosilicate, preferably a zeolite, based on thealuminosilicate, preferably 30 to 99.9 wt %, preferably selected fromthe group consisting of ZSM-5, ZSM-11, ZSM-12, ZSM-23, or ZSM-35,preferably converted to the H+form, preferably having a SiO₂/Al₂O₃ molarratio of from 20:1 to 80:1, and (4) a binder, preferably selected fromsilica, alumina and mixtures thereof.

The unreacted methane and byproduct hydrocarbons may be used in othersteps, stored and/or recycled. It may be necessary to cool thesebyproducts to liquefy them. When the ethane or mixed lower alkanesoriginate from an LNG plant as a result of the purification of thenatural gas, at least some of these byproducts may be cooled andliquefied using the heat exchangers used to liquefy the purified naturalgas (methane).

The toluene and xylene may be converted into benzene byhydrodealkylation. The hydrodealkylation reaction involves the reactionof toluene, xylenes, ethylbenzene, and higher aromatics with hydrogen tostrip alkyl groups from the aromatic ring to produce additional benzeneand light ends including methane and ethane which are separated from thebenzene. This step substantially increases the overall yield of benzeneand thus is highly advantageous.

Both thermal and catalytic hydrodealkylation processes are known in theart. Methods for hydrodealkylation are described in U.S. PatentApplication Publication No. 2009/0156870 which is herein incorporated byreference in its entirety.

The integrated process of this invention may also include the reactionof benzene with propylene to produce cumene which may in turn beconverted into phenol and/or acetone. The propylene may be producedseparately in a propane dehydrogenation unit or may come from olefincracker process vent streams or other sources. Methods for the reactionof benzene with propylene to produce cumene are described in U.S. PatentApplication Publication No. 2009/0156870 which is herein incorporated byreference in its entirety.

The integrated process of this invention may also include the reactionof benzene with olefins such as ethylene. The ethylene may be producedseparately in an ethane dehydrogenation unit or may come from olefincracker process vent streams or other sources. Ethylbenzene is anorganic chemical compound which is an aromatic hydrocarbon. Its majoruse is in the petrochemical industry as an intermediate compound for theproduction of styrene, which in turn is used for making polystyrene, acommonly used plastic material. Methods for the reaction of benzene withethylene to produce ethylbenzene are described in U.S. PatentApplication Publication No. 2009/0156870 which is herein incorporated byreference in its entirety.

Styrene may then be produced by dehydrogenating the ethylbenzene. Oneprocess for producing styrene is described in U.S. Pat. No. 4,857,498which is herein incorporated by reference in its entirety. Anotherprocess for producing styrene is described in U.S. Pat. No. 7,276,636which is herein incorporated by reference in its entirety.

EXAMPLES

The following examples are provided for illustrative purposes only andare not intended to limit the scope of the invention.

Example 1

Indane and indene were obtained from vendors. Toluene was used as abenchmark in this study of the fuel blending properties. The RON and MONof neat indane, indene, toluene, and a base fuel were tested using ASTMD-2699 and ASTM D-2700 test method. All compounds were tested intriplicate and the average of those results were presented in Table 2.The RON and MON of the base fuel and toluene were reasonably high asexpected and the RON and MON of indane and indene were also reasonablehigh.

TABLE 2 Neat Density Average delta g/ml RON MON R + M/2 R − M 0.743 BaseFuel 85.4 79.0 82.1 6.5 0.865 Toluene 114.5 106.0 110.3 8.5 0.965 Indane100.7 85.5 93.1 15.2 0.996 Indene 108.0 98.5 103.2 9.5

The RON and MON of 1.2 v % indane and indene in base fuel blends weremeasured (see the top part of Table 3). The RON and MON of 3.7 v %toluene, 4.7 v % indane and 4.6 v % indene in base fuel blends were alsomeasured (see the bottom part of Table 3). Table 3 below shows anincrease in Research Octane Number of 0.43 and 0.5 with 1.2v % of indaneand indene, respectively. Table 3 shows an increase in Research OctaneNumber of 0.90 and 0.80 with 4.7 v % of indane and 4.6 v % indene,respectively.

TABLE 3 Average delta Density R + R + (g/ml) RON MON M/2 RON MON M/20.743 Base Fuel (BF) 86.3 79.8 83.0 0.965 Indane 86.7 79.8 83.2 0.43−0.03 0.2 (1.2 v % in BF) 0.996 Indene (1.2 v %) 86.8 79.5 83.1 0.50−0.30 0.1 0.743 Base Fuel 86.67 79.83 83.3 0.865 Toluene (3.7 v %) 87.680.23 83.9 0.93 0.40 0.7 0.965 Indane (4.7 v %) 87.57 80.23 83.9 0.900.40 0.6 0.996 Indene (4.6 v %) 87.47 79.57 83.5 0.80 −0.27 0.2

Such increase in octane number is known in the literature for aromaticmolecules. However, it is generally compensated for by a decrease inflame speed. The flame speeds of above molecules were measured using theLeeds University bomb experiment technique at Leeds University facility.Fuel samples were tested under laminar conditions with initialconditions of 5 bar absolute pressure and 360K. All the burningvelocities (flame speed) were measured at stoichiometric ratio of fuelto air. The experiments were conducted using the Leeds Mkt fan stirredcombustion vessel (Refer to www.engineering.leeds.ac.uk/mech for theirfacility). It is a stainless sphere of 30 liter volume with extensiveoptical access. The fuels were injected into the bomb and allowed tovaporize fully, then a stoichometric amount of air was added. Contentwere heated to the desired temperature, mixed by stirring. Mixing fanswere turned off prior to ignition. Pressure measured after 0.1 second ofthe ignition is recorded in Table 4. To determine if there was anysignificant change due to the presence of a component, it was decided todo experiments using 20 v % of the components in commercial gradegasoline. No significant change in flame speed was noted for indane orindene as shown in Table 4. The data in Tables 1-4 indicate that indane,indene, other C₉ aromatics, and certain C₁₀ aromatics other thannaphthalene would comprise suitable gasoline blending components.

TABLE 4 Flame Speed Data Blend Composition Flame Speed Molecule % inGasoline P/bar at 0.1 Second Gasoline 100 17.35 Indane 20 17.24 Indene20 16.10

Example 2

Four runs were carried out in a lab-scale aromatization reactor at 0kPag, 600° C. reactor wall temperature with repeated cycles of 10 minuteexposure of the catalyst to feed followed by 20 minute exposure of thecatalyst to hot hydrogen stripping. The feed and other conditions aredescribed in Table 5 below. The catalysts used in these runs wereprepared as described in U.S. Patent Application Publication No.2009/02009794, which is incorporated by reference, with target metalloadings of 0.025 wt % platinum and 0.09 wt % gallium or 0.09 wt %platinum and 0.25 wt % gallium, on extrudates consisting of 80 wt %ZSM-5 CBV 2314 zeolite (available from Zeolyst International) and 20 wt% alumina binder. A gas chromatograph was used to provide quantitativeanalysis of the total product stream.

As shown in Table 5, the total C₉₊ aromatics fraction accounted forabout 8-15 wt % of the total aromatics product in runs conducted withall-ethane and mixed ethane/propane feeds. The C₉₋₁₀ aromatics fractionexcluding naphthalene ranged between about 45 and 60% w of the total C₉₊aromatics product or about 4-8% w of the total aromatics product inthese runs.

TABLE 5 Run No. 1 2 3 4 Feed Composition Ethane, % wt 100 100 50 50Propane, % wt -0- -0- 50 50 Feed Rate, GHSV 800 800 1000 1000 Total Hrson Feed 14.4 50.7 27.2 50.7 Avg Total C2 + C3 Conversion per 38.40 33.6647.26 47.06 Pass, % Avg Total Arom. Yield per Pass, 23.57 20.01 30.1932.81 % wt Avg C9+ Arom. Yield per Pass, 3.29 2.61 3.30 2.95 % wt AvgC9-C10 Arom. (Except Naphthalane) Yield as % of C9+ Aromatics 45.3 59.856.7 48.5 Yield as % of Total Aromatics 6.3 7.8 6.2 4.4 Avg Naphthaleneand Higher Aromatics Yield as % of C9+ Aromatics 54.7 40.2 43.3 51.5Yield as % of Total Aromatics 7.6 5.2 4.7 4.6 Final Boiling Point ofCollected NA 493 NA 453 Liquid Product, ° C.

What is claimed is:
 1. An integrated process for producing gasolineblending components and aromatic hydrocarbons which comprises: (a)contacting a lower alkane feed with an aromatic hydrocarbon conversioncatalyst to produce an aromatic reaction product mixture which iscomprised of benzene and/or toluene and/or xylene, C9 aromatic products,C10 aromatic products including naphthalene and, optionally, C11+aromatic products, (b) separating and recovering the aromatic reactionproduct mixture, (c) separating and recovering benzene, and (d)separating and recovering toluene and/or xylene and the C9 aromaticproducts and the C10 aromatic products which boil at a lower temperaturethan naphthalene from the naphthalene and the C10 aromatic reactionproducts which boil at a higher temperature than naphthalene and anyC11+ aromatic products.
 2. A process as claimed in claim 1 wherein step(d) further comprises separating and recovering toluene and/or xyleneand separating and recovering the C9 aromatic products and the C10aromatic products which boil at a lower temperature than naphthalene. 3.A process as claimed in claim 1 further comprising hydrodealkylating thetoluene and/or xylene to produce additional benzene.
 4. A process asclaimed in claim 1 wherein the C9 aromatic products and the C10 aromaticproducts which boil at a lower temperature than naphthalene comprisesindane, methyl indane, indene, methyl indene or mixtures thereof.